The present invention relates to compounds that are useful as protease inhibitors, particularly as serine protease inhibitors, and more particularly as hepatitis C NS3 protease inhibitors. As such, they act by interfering with the life cycle of the hepatitis C virus and are also useful as antiviral agents.
This invention also relates to pharmaceutical compositions comprising these compounds. The compounds and pharmaceutical compositions of this invention are particularly well suited for inhibiting HCV NS3 protease activity and consequently, may be advantageously used as therapeutic agents against the hepatitis C virus and other viruses that are dependent upon a serine protease for proliferation. This invention also relates to methods for inhibiting the activity of proteases, including hepatitis C virus NS3 protease and other serine proteases, using the compounds of this invention and related compounds.
Infection by hepatitis C virus (xe2x80x9cHCVxe2x80x9d) is a compelling human medical problem. HCV is recognized as the causative agent for most cases of non-A, non-B hepatitis, with an estimated human seroprevalence of 1% globally [Purcell, R. H., xe2x80x9cHepatitis C virus: Historical perspective and current conceptsxe2x80x9d FEMS Microbiology Reviews 14, pp. 181-192 (1994); Van der Poel, C. L., xe2x80x9cHepatitis C Virus. Epidemiology, Transmission and Prevention in Hepatitis C Virus. Current Studies in Hematology and Blood Transfusion, H. W. Reesink, Ed., (Basel: Karger), pp. 137-163 (1994)]. Four million individuals may be infected in the United States alone [Alter, M. J. and Mast, E. E., xe2x80x9cThe Epidemiology of Viral Hepatitis in the United States, Gastroenterol. Clin. North Am. 23, pp. 437-455 (1994)].
Upon first exposure to HCV only about 20% of infected individuals develop acute clinical hepatitis while others appear to resolve the infection spontaneously. In most instances, however, the virus establishes a chronic infection that persists for decades [Iwarson, S. xe2x80x9cThe Natural Course of Chronic Hepatitisxe2x80x9d FEMS Microbiology Reviews 14, pp. 201-204 (1994)]. This usually results in recurrent and progressively worsening liver inflammation, which often leads to more severe disease states such as cirrhosis and hepatocellular carcinoma [Kew, M. C., xe2x80x9cHepatitis C and Hepatocellular Carcinomaxe2x80x9d, FEMS Microbiology Reviews, 14, pp. 211-220 (1994); Saito, I., et al. xe2x80x9cHepatitis C Virus Infection is Associated with the Development of Hepatocellular Carcinomaxe2x80x9d Proc. Natl. Acad. Sci. USA 87, pp. 6547-6549 (1990)]. Unfortunately, there are no broadly effective treatments for the debilitating progression of chronic HCV.
The HCV genome encodes a polyprotein of 3010-3033 amino acids [Choo, Q. -L., et al. xe2x80x9cGenetic organization and Diversity of the Hepatitis C Virusxe2x80x9d, Proc. Natl. Acad. Sci. USA, 88, pp. 2451-2455 (1991); Kato, N. et al., Molecular Cloning of the Human Hepatitis C Virus Genome From Japanese Patients with Non-A, Non-B Hepatitisxe2x80x9d, Proc. Natl. Acad. Sci. USA, 87, pp. 9524-9528 (1990); Takamizawa, A. et al., xe2x80x9cStructure and organization of the Hepatitis C Virus Genome Isolated From Human Carriersxe2x80x9d, J. Virol., 65, pp. 1105-1113 (1991)]. The HCV nonstructural (NS) proteins are presumed to provide the essential catalytic machinery for viral replication. The NS proteins are derived by proteolytic cleavage of the polyprotein [Bartenschlager, R. et al., xe2x80x9cNonstructural Protein 3 of the Hepatitis C Virus Encodes a Serine-Type Proteinase Required for Cleavage at the NS3/4 and NS4/5 Junctionsxe2x80x9d, J. Virol., 67, pp. 3835-3844 (1993); Grakoui, A. et al. xe2x80x9cCharacterization of the Hepatitis C Virus-Encoded Serine Proteinase: Determination of Proteinase-Dependent Polyprotein Cleavage Sitesxe2x80x9d, J. Virol., 67, pp. 2832-2843 (1993); Grakoui, A. et al., Expression and Identification of Hepatitis C Virus Polyprotein Cleavage Productsxe2x80x9d, J. Virol., 67, pp. 1385-1395 (1993); Tomei, L. et al., xe2x80x9cNS3 is a serine protease required for processing of hepatitis C virus polyproteinxe2x80x9d, J. Virol., 67, pp. 4017-4026 (1993)].
The HCV NS protein 3 (NS3) contains a serine protease activity that helps process the majority of the viral enzymes, and is thus considered essential for viral replication and infectivity. It is known that mutations in the yellow fever virus NS3 protease decreases viral infectivity [Chambers, T. J. et. al., xe2x80x9cEvidence that the N-terminal Domain of Nonstructural Protein NS3 From Yellow Fever Virus is a Serine Protease Responsible for Site-Specific Cleavages in the Viral Polyproteinxe2x80x9d, Proc. Natl. Acad. Sci. USA, 87, pp. 8898-8902 (1990)]. The first 181 amino acids of NS3 (residues 1027-1207 of the viral polyprotein) have been shown to contain the serine protease domain of NS3 that processes all four downstream sites of the HCV polyprotein [C. Lin et al., xe2x80x9cHepatitis C Virus NS3 Serine Proteinase: Trans-Cleavage Requirements and Processing Kineticsxe2x80x9d, J. Virol., 68, pp. 8147-8157 (1994)].
The HCV NS3 serine protease and its associated cofactor, NS4A, helps process all of the viral enzymes, and is thus considered essential for viral replication. This processing appears to be analogous to that carried out by the human immunodeficiency virus aspartyl protease, which is also involved in viral enzyme processing HIV protease inhibitors, which inhibit viral protein processing are potent antiviral agents in man, indicating that interrupting this stage of the viral life cycle results in therapeutically active agents. Consequently it is an attractive target for drug discovery. Unfortunately, there are no serine protease inhibitors available currently as anti-HCV agents.
Furthermore, the current understanding of HCV has not led to any other satisfactory anti-HCV agents or treatments. The only established therapy for HCV disease is interferon treatment. However, interferons have significant side effects (Janssen et al., 1994; Renault and Hoofnagle, 1989) [Janssen, H. L. A., et al. xe2x80x9cSuicide Associated with Alfa-Interferon Therapy for Chronic Viral Hepatitisxe2x80x9d J. Hepatol., 21, pp. 241-243 (1994)]; Renault, P. F. and Hoofnagle, J. H., xe2x80x9cSide effects of alpha interferon. Seminars in Liver Disease 9, 273-277. (1989)] and induce long term remission in only a fraction (xcx9c25%) of cases [Weiland, O. xe2x80x9cInterferon Therapy in Chronic Hepatitis C Virus Infectionxe2x80x9d, FEMS Microbiol. Rev., 14, PP. 279-288 (1994)]. Moreover, the prospects for effective anti-HCV vaccines remain uncertain.
Thus, there is a need for more effective anti-HCV therapies. Such inhibitors would have therapeutic potential as protease inhibitors, particularly as serine protease inhibitors, and more particularly as HCV NS3 protease inhibitors. Specifically, such compounds may be useful as antiviral agents, particularly as anti-HCV agents.
The present invention provides compounds, and pharmaceutically acceptable derivatives thereof, that are useful as protease inhibitors, particularly as serine protease inhibitors, and more particularly as HCV NS3 protease inhibitors. These compounds can be used alone or in combination with immunomodulatory agents, such as xcex1-, xcex2- or xcex3-interferons; other antiviral agents such as ribavirin and amantadine; other inhibitors of hepatitis C protease; inhibitors of other targets in the HCV life cycle including the helicase, polymerase, metalloprotease, or internal ribosome entry; or combinations thereof.
The present invention also provides methods for inhibiting proteases, particularly serine proteases, and more particularly HCV NS3 protease.
The present invention also provides pharmaceutical compositions comprising the compounds of this invention, as well as multi-component compositions comprising additional immunomodulatory agents, such as xcex1-, xcex2- or xcex3-interferons; other antiviral agents such as ribavirin and amantadine; other inhibitors of hepatitis C protease; inhibitors of other targets in the HCV life cycle including the helicase, polymerase, metalloprotease, or internal ribosome entry; or combinations thereof. The invention also provides methods of using the compounds of this invention, as well as other related compounds, for the inhibition of HCV.
In order that the invention herein described may be more fully understood, the following detailed description is set forth. In the description, the following abbreviations are used:
The following terms are used herein:
Unless expressly stated to the contrary, the terms xe2x80x9cxe2x80x94SO2xe2x80x94xe2x80x9d and xe2x80x9cxe2x80x94S(O)2xe2x80x94xe2x80x9d as used herein refer to a sulfone or sulfone derivative (i.e., both appended groups linked to the S), and not a sulfinate ester.
The term xe2x80x9csubstitutedxe2x80x9d refers to the replacement of one or more hydrogen radicals in a given structure with a radical selected from a specified group. When more than one hydrogen radical may be replaced with a substituent selected from the same specified group, the substituents may be either the same or different at every position.
As used herein, the term xe2x80x9caminoxe2x80x9d refers to a trivalent nitrogen which may be primary or which may be substituted with 1-2 alkyl groups.
The term xe2x80x9calkylxe2x80x9d or xe2x80x9calkanexe2x80x9d, alone or in combination with any other term, refers to a straight-chain or branched-chain saturated aliphatic hydrocarbon radical containing the specified number of carbon atoms, or where no number is specified, preferably from 1-10 and more preferably from 1-5 carbon atoms. Examples of alkyl radicals include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isoamyl, n-hexyl and the like.
The term xe2x80x9calkenylxe2x80x9d or xe2x80x9calkenexe2x80x9d, alone or in combination with any other term, refers to a straight-chain or branched-chain mono- or poly-unsaturated aliphatic hydrocarbon radical containing the specified number of carbon atoms, or where no number is specified, preferably from 2-10 carbon atoms and more preferably, from 2-5 carbon atoms. Examples of alkenyl radicals include, but are not limited to, ethenyl, E- and Z-propenyl, E- and Z-isobutenyl, E- and Z-pentenyl, E- and Z-hexenyl, E,E-, E,Z-, Z,E-, and Z-Z-hexadienyl and the like.
The term xe2x80x9calkynylxe2x80x9d or xe2x80x9calkynexe2x80x9d, alone or in combination with any other term, refers to a straight-chain or branched-chain mono or poly-unsaturated aliphatic hydrocarbon radical containing the specified number of carbon atoms, or where no number is specified, preferably from 2-10 carbon atoms and more preferably, from 2-5 carbon atoms, wherein at least one of the unsaturated aliphatic hydrocarbon radicals comprises a triple bond. Examples of alkynyl radicals include, but are not limited to, ethynyl, propynyl, isobutynyl, pentynyl, hexynyl, hexenynyl, and the like.
The term xe2x80x9carylxe2x80x9d, alone or in combination with any other term, refers to a carbocyclic aromatic radical containing the specified number of carbon atoms, and which may be optionally fused, for example benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. Preferred aryl groups have from 6-14 carbon atoms, and more preferred groups from 6-10 carbon atoms. Examples of aryl radicals include, but are not limited to, phenyl, naphthyl, anthracenyl and the like.
The term xe2x80x9ccarbocyclexe2x80x9d, alone or in combination with any other term, refers to a stable non-aromatic 3- to 8-membered carbon ring radical which may be saturated, Amono-unsaturated or poly-unsaturated, and which may be optionally fused, for example benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. The carbocycle may be attached at any endocyclic carbon atom which results in a stable structure.
The terms xe2x80x9ccycloalkylxe2x80x9d or xe2x80x9ccycloalkanexe2x80x9d, alone or in combination with any other term, refers to a stable non-aromatic 3- to 8-membered carbon ring radical which is saturated and which may be optionally fused, for example benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. The cycloalkyl may be attached at any endocyclic carbon atom which results in a stable structure. Preferred carbocycles have 5 to 6 carbons. Examples of carbocycle radicals include, but are not limited to, cyclopropyl, cyclbutyl, cyclpentyl, cyclohexyl, cycloheptyl, cyclopentenyl, cyclohexenyl, indane, tetrahydronaphthalene and the like.
The term xe2x80x9ccycloalkenylxe2x80x9d or xe2x80x9ccycloalkenexe2x80x9d alone or in combination with any other term, refers to a stable cyclic hydrocarbon ring radical containing at least one endocyclic carbon-carbon double bond. The carbocycle may be attached at any cyclic carbon atom which results in a stable structure. Where no number of carbon atoms is specified, a cycloalkenyl radical preferably has from 5-7 carbon atoms. Examples of cycloalkenyl radicals include, but are not limited to, cyclopentenyl, cyclohexenyl, cyclopentadienyl, indenyl and the like.
The term xe2x80x9ccycloalkylidenylxe2x80x9d, alone or in combination with any other term, refers to a stable cyclic hydrocarbon ring radical containing at least one exocyclic carbon-carbon double bond, wherein the cyclic hydrocarbon ring may be optionally fused, for example benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. The carbocycle may be attached at any cyclic carbon atom, which results in a stable structure. Where no number of carbon atoms is specified, a cycloalkylidenyl radical preferably has from 5-7 carbon atoms. Examples of cycloalkylidenyl radicals include, but are not limited to, cyclopentylidenyl, cyclohexylidenyl, cyclopentenylidenyl and the like.
The skilled practitioner would realize that certain groups could be classified either as cycloalkanes or as aryl groups. Examples of such groups include indanyl and tetrahydro naphthyl groups.
The term xe2x80x9cmonocyclexe2x80x9d or xe2x80x9cmonocyclicxe2x80x9d alone or in combination with any other term, unless otherwise defined herein, refers to a 5-7 membered ring system.
The term xe2x80x9cbicyclexe2x80x9d or xe2x80x9cbicyclicxe2x80x9d alone or in combination with any other term, unless otherwise defined herein, refers to a 6-11 membered ring system.
The term xe2x80x9ctricyclexe2x80x9d or xe2x80x9ctricyclicxe2x80x9d alone or in combination with any other term, unless otherwise defined herein, refers to a 11-15 membered ring system.
The terms xe2x80x9cheterocyclylxe2x80x9d and xe2x80x9cheterocyclexe2x80x9d, alone or in combination with any other term, unless otherwise defined herein, refers to a stable 5- to 15-membered mono-, bi-, or tricyclic, heterocyclic ring which is either saturated or partially unsaturated, but not aromatic, and which may be optionally fused, for example benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. Each heterocycle consists of one or more carbon atoms and from one to four heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. As used herein, the terms xe2x80x9cnitrogen and sulfur heteroatomsxe2x80x9d include any oxidized form of nitrogen and sulfur, and the quaternized form of any basic nitrogen. A heterocycle may be attached at any endocyclic carbon or heteroatom which results in the creation of a stable structure.
Preferred heterocycles defined above include, for example, imidazolidinyl, indazolinolyl, perhydropyridazyl, pyrrolinyl, pyrrolidinyl, piperidinyl, pyrazolinyl, piperazinyl, morpholinyl, thiamorpholinyl, xcex2-carbolinyl, thiazolidinyl, thiamorpholinyl sulfone, oxopiperidinyl, oxopyrroldinyl, oxoazepinyl, azepinyl, furazanyl, tetrahydropyranyl, tetrahydrofuranyl, oxathiolyl, dithiolyl, tetrahydrothiophenyl, dioxanyl, dioxolanyl, tetrahydrofurotetrahydrofuranyl, tetrahydropyranotetrahydrofuranyl, tetrahydrofurodihydrofuranyl, tetrahydropyranodihydrofuranyl, dihydropyranyl, dihydrofuranyl, dihydrofurotetrahydrofuranyl, dihydropyranotetrahydrofuranyl, sulfolanyl and the like.
The terms xe2x80x9cheteroarylxe2x80x9d and xe2x80x9cheteroaromaticxe2x80x9d alone or in combination with any other term, unless otherwise defined herein, refers to a stable 3- to 7-membered monocyclic heterocyclic ring which is aromatic, and which may be optionally fused, for example, benzofused, with one to three cycloalkyl, aromatic, heterocyclic or heteroaromatic rings. Each heteroaromatic ring consists of one or more carbon atoms and from one to four heteroatoms selected from the group consisting of nitrogen, oxygen and sulfur. As used herein, the terms xe2x80x9cnitrogen and sulfur heteroatomsxe2x80x9d include any oxidized form of nitrogen and sulfur, and the quaternized form of any basic nitrogen. A heteroaromatic ring may be attached at any endocyclic carbon or heteroatom which results in the creation of a stable, aromatic structure.
Preferred heteroaromatics defined above include, for example, benzimidazolyl, imidazolyl, quinolyl, isoquinolyl, indolyl, indazolyl, pyridazyl, pyridyl, pyrrolyl, pyrazolyl, pyrazinyl, quinoxolyl, pyranyl, pyrimidinyl, pyridazinyl, furyl, thienyl, triazolyl, thiazolyl, tetrazolyl, benzofuranyl, oxazolyl, benzoxazolyl, isoxazolyl, isothiazolyl, thiadiazolyl, thiophenyl, oxadiazolyl, oxatriazolyl, thiatriazolyl, dithiazolyl, dioxazolyl, oxathiazolyl, triazinyl and the like.
The term xe2x80x9chaloxe2x80x9d refers to a radical of fluorine, chlorine, bromine or iodine. Preferred halogen radicals include fluorine and chlorine.
In chemical formulas, parentheses are used herein to indicate 1) the presence of more than one atom or group bonded to the same atom or group; or 2) a branching point in a chain (i.e., the group or atom immediately before the open parenthesis is bonded directly to the group or atom immediately after the closed parenthesis). An example of the first use is xe2x80x9cN(R1)2xe2x80x9d denoting two R1 groups bound to the nitrogen atom. An example of the second use is xe2x80x9cxe2x80x94C(O)R1xe2x80x9d denoting an oxygen atom and a R1 bound to the carbon atom, as in the following structure: 
As used herein, xe2x80x9cBxe2x80x9d indicates a boron atom.
Those of skill in the art will realize that certain combinations of moiety choices for variables in the generic structures set forth throughout this application will produce chemically unstable or unfeasible compounds. Such compounds are not intended to be part of the present invention.
The present invention provides compounds that are useful as protease inhibitors, particularly as serine protease inhibitors, and more particularly as HCV NS3 protease inhibitors. As such, they act by interfering with the life cycle of the HCV virus and other viruses that are dependent upon a serine protease for proliferation. Therefore, these compounds are useful as antiviral agents.
According to one embodiment, the present invention provides a compound of the formula (I): 
In these compounds W is selected from: 
wherein m is 0 or 1.
Each R1 is hydroxy, alkoxy, or aryloxy, or each R1 is an oxygen atom and together with the boron, to which they are each bound, form a 5-7 membered ring, wherein the ring atoms are carbon, nitrogen, or oxygen.
Each R2 is independently hydrogen, halo, alkyl, alkenyl, aryl, aralkyl, aralkenyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, cycloalkenylalkyl, heterocyclyl, heterocyclylalkyl, heterocyclylalkenyl, heteroaryl, or heteroaralkyl, or two R2 groups, which are bound to the same nitrogen atom, form together with that nitrogen atom, a 5-7 membered monocyclic heterocyclic ring system; wherein any R2 carbon atom is optionally substituted with J.
Each J is independently alkyl, aryl, aralkyl, alkoxy, aryloxy, aralkoxy, cycloalkyl, cycloalkoxy, heterocyclyl, heterocyclyloxy, heterocyclylalkyl, keto, hydroxy, amino, alkylamino, alkanoylamino, aroylamino, aralkanoylamino, carboxy, carboxyalkyl, carboxamidoalkyl, halo, cyano, nitro, formyl, acyl, sulfonyl, or sulfonamido and is optionally substituted with 1 to 3 J1 groups.
Each J1 is independently selected from alkyl, aryl, aralkyl, alkoxy, aryloxy, heterocyclyl, heterocyclyloxy, keto, hydroxy, amino, alkanoylamino, aroylamino, carboxy, carboxyalkyl, carboxamidoalkyl, halo, cyano, nitro, formyl, sulfonyl, or sulfonamido.
L is alkyl, alkenyl, or alkynyl, wherein any hydrogen bound to a carbon atoms is optionally substituted with halogen, and wherein any hydrogen or halogen atom bound to any terminal carbon atom is optionally substituted with sulfhydryl or hydroxy.
Each M is independently alkyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, or heteroaralkyl, and is optionally substituted by 1 to 3 J groups, wherein any alkyl carbon atom may be replaced by a heteroatom.
R18 is a bond, xe2x80x94N(R11)xe2x80x94, or xe2x80x94C(O)xe2x80x94.
R11 is hydrogen or C1-C3 alkyl.
Each R19 is independently H or R21-aryl, or 2 adjacent R19 may be bound to one another to form a 5-7 membered aromatic ring, wherein any R19 is optionally substituted with 1 to 4 independently selected Jxe2x80x2 groups. When 2 adjacent R19 are bound to one another to form a 5-7 membered aromatic ring a bicyclic ring system is formed consisting of the aromatic ring shown in formula I and the aromatic ring formed by two adjacent R19 groups. When R19 is R21-aryl, this optional substitution may occur on one or more carbon atoms of R21 and/or on one or more ring atoms of said aryl. When 2 adjacent R19 are bound to one another to form a 5-7 membered aromatic ring, the optional substitution may occur on one or more atoms of the resulting aromatic ring.
Each R21 is independently C1-C3-straight or branched alkyl, C2-C3-straight or branched alkenyl, Oxe2x80x94(C1-C3)-straight or branched alkyl, or Oxe2x80x94(C2-C3)-straight or branched alkenyl.
n is 0 or 1.
The ring to which R18 and R19 are attached may be saturated, partially saturated, aromatic or fully unsaturated. Up to 3 carbon atoms that make up the ring to which R18 and R19 are attached are optionally replaced with a heteroatom which is independently selected from O, S, S(O), S(O)2 or N(R11).
A2 is a bond or xe2x80x94N(R11)xe2x80x94R17(M)xe2x80x94R22xe2x80x94, wherein R17 is xe2x80x94CHxe2x80x94 or xe2x80x94Nxe2x80x94; and R22 is xe2x80x94C(O)xe2x80x94 or xe2x80x94S(O)2xe2x80x94.
V is a bond, xe2x80x94CH(R )xe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, or xe2x80x94N(R11)xe2x80x94.
K is a bond, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94C(O)xe2x80x94, xe2x80x94S(O)xe2x80x94, xe2x80x94S(O)2xe2x80x94, or xe2x80x94S(O)NR11xe2x80x94.
T is xe2x80x94R12, -alkyl-R12, -alkenyl-R12, -alkynyl-R12, -OR12, xe2x80x94N(R12)2, xe2x80x94C(O)R12, xe2x80x94C(xe2x95x90NO-alkyl)R12 or 
Each R12 is independently selected from hydrogen, aryl, heteroaryl, cycloalkyl, heterocyclyl, cycloalkylidenyl, or heterocycloalkylidenyl, and is optionally substituted with 1 to 3 J groups; or a first R12 and a second R12, together with the nitrogen to which they are bound, form a mono- or bicyclic ring system optionally substituted by 1 to 3 J groups.
R10 is alkyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, heteroaralkyl, carboxyalkyl, or carboxamidoalkyl, and is optionally substituted with 1 to 3 J groups.
R15 is alkyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heterocyclylalkyl, heteroaryl, heteroaralkyl, carboxyalkyl, or carboxamidoalkyl, and is optionally substituted with 1 to 3 J groups.
R16 is hydrogen, alkyl, aryl, heteroaryl, cycloalkyl, or heterocyclyl.
Preferably, W is 
More preferably, W is 
Even more preferably, W is 
wherein R2 is aralkyl; or 
Most preferably, W is xe2x80x94C(O)H.
Preferably, J is alkyl, alkoxy, aryloxy, aryl, ralkyl, aralkoxy, halo, heteroaryl, cyano, amino, nitro, heterocyclyl, acyl, carboxy, carboxyalkyl, alkylamino, hydroxy, heterocyclylalkyl, aralkanoylamino, aroylamino, alkanoylamino, formyl or keto.
More preferably, J is t-butyl, methyl, trifluoromethyl, hydroxy, methoxy, ethoxy, trifluoromethoxy, carboxy, phenyl, benzyl, phenoxy, benzyloxy, fluoro, chloro, bromo, isoxazolyl, pyridinyl, piperidinyl, carboxymethyl, carboxyethyl, dialkylamino, morpholinylmethyl, phenylacetylamino, or acylamino.
Preferably, J1 is alkoxy, alkyl, halo or aryl.
More preferably, J1 is C1-3 alkoxy, chloro, C1-3 alkyl, or phenyl.
Preferably, L is alkyl, alkenyl, allyl, or propargyl.
More preferably, L is trihalomethyl, sulfhydryl or alkyl substituted with trihalomethyl, sulfhydryl, or hydroxy. Most preferably, L is xe2x80x94CH2CH3 or xe2x80x94CH2CF3.
Preferably, R2 is H, fluorine, trifluoromethyl, alkyl, aryl, aralkyl, heteroaralkyl, heterocyclyl, or heterocyclylalkyl. More preferred is when R2 is H.
Preferably, M is alkyl, heteroaralkyl, aryl, cycloalkylalkyl, aralkyl, or aralkyl, wherein one of the alkyl carbon atoms is replaced by O or S.
More preferably M is isopropyl, propyl, methyl, pyridylmethyl, benzyl, naphthylmethyl, phenyl, imidazolylmethyl, thiophenylmethyl, cyclohexylmethyl, phenethyl, benzylthiomethyl, or benzyloxyethyl. Most preferably, M is isopropyl.
Preferably, one R19 is R21-aryl and the other two R19 are H or two R19 are bound together to form an aromatic ring and the other R19 is H. More preferred is when one R19 is xe2x80x94Oxe2x80x94(C1-C3)-alkyl-aryl or the two R19 bound together form a 6-membered aromatic ring. Most preferred is when one R19 is xe2x80x94O-benzyl or the two R19 bound together form phenyl.
Preferably, R18 is xe2x80x94N(R11)xe2x80x94. More preferably, R18 is xe2x80x94N(H)xe2x80x94 or xe2x80x94N(CH3)xe2x80x94.
Preferably, the ring to which R18 and R19 are attached is aromatic.
It is preferred that A2 be a bond or xe2x80x94N(R11)xe2x80x94C(M)xe2x80x94C(O)xe2x80x94. More preferred is when A2 is a bond or xe2x80x94N(H)xe2x80x94C(M)xe2x80x94C(O)xe2x80x94, wherein M is isopropyl.
Preferably, V is xe2x80x94N(R11)xe2x80x94. More preferably, V is xe2x80x94NHxe2x80x94.
Preferably, K is xe2x80x94C(O)xe2x80x94 or xe2x80x94S(O)2xe2x80x94. More preferably, K is xe2x80x94C(O)xe2x80x94
Preferably, T is xe2x80x94R12, -alkyl-R12, -alkenyl-R12, xe2x80x94OR12, xe2x80x94N(R12)2, xe2x80x94C(xe2x95x90NO-alkyl)-R12, or 
More preferably, T is xe2x80x94R12 or -alkyl-R12.
Preferably, R12 is aryl or heteroaryl and is optionally substituted by 1-3 J groups. More preferably, R12 is naphthyl, pyrazinyl, or pyridyl, any of which is optionally substituted with a hydroxy group
Preferably, R10 is alkyl substituted with carboxy. More preferably, R10 is C1-3 alkyl substituted with carboxy.
Preferably, R15 is alkyl substituted with carboxy. More preferably, R15 is C1-3 alkyl substituted with carboxy.
The most preferred compounds of this invention are listed in Table 1, below.
This invention anticipates that many active-site directed inhibitors of the NS3 protease may be peptidomimetic in nature and thus may be designed from the natural substrate. Therefore, preferred substituents in peptidomimetic inhibitors of this invention include those which correspond to the backbone or side chains of naturally occurring substrates or synthetic substrates with high affinity for the enzyme (low Km).
The skilled practitioner would realize that some certain groups could be classified either as heterocycles or heteroaromatics, depending on the point of attachment.
The compounds of this invention may contain one or more asymmetric carbon atoms and thus may occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. All such isomeric forms of these compounds are expressly included in the present invention. Each stereogenic carbon may be of the R or S configuration. Combinations of substituents and variables envisioned by this invention are only those that result in the formation of stable compounds. The term xe2x80x9cstablexe2x80x9d, as used herein, refers to compounds which possess stability sufficient to allow manufacture and which maintains the integrity of the compound for a sufficient period of time to be useful for the purposes detailed herein (e.g., therapeutic or prophylactic administration to a mammal or for use in affinity chromatography applications). Typically, such compounds are stable at a temperature of 40xc2x0 C. or less, in the absence of moisture or other chemically reactive conditions, for at least a week.
The compounds of this invention may be synthesized using conventional techniques. Advantageously, these compounds are conveniently synthesized from readily available starting materials.
As used herein, the compounds of this invention are defined to include pharmaceutically acceptable derivatives or prodrugs thereof. A xe2x80x9cpharmaceutically acceptable derivative or prodrugxe2x80x9d means any pharmaceutically acceptable salt, ester, salt of an ester, or other derivative of a compound of this invention which, upon administration to a recipient, is capable of providing (directly or indirectly) a compound of this invention.
Accordingly, this invention also provides prodrugs of the compounds of this invention, which are derivatives that are designed to enhance biological properties such as oral absorption, clearance, metabolism or compartmental distribution. Such derivations are well known in the art.
As the skilled practitioner realizes, the compounds of this invention may be modified by appending appropriate functionalities to enhance selective biological properties. Such modifications are known in the art and include those which increase biological penetration into a given biological compartment (e.g., blood, lymphatic system, central nervous system), increase oral availability, increase solubility to allow administration by injection, alter metabolism and alter rate of excretion.
The term xe2x80x9cprotectedxe2x80x9d refers to when the designated functional group is attached to a suitable chemical group (protecting group). Examples of suitable amino protecting groups and protecting groups are described in T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 2d. Ed., John Wiley and Sons (1991); L. Fieser and M. Fieser, Fieser and Fieser""s Reagents for Organic Synthesis, John Wiley and Sons (1994); L. Paquette, ed. Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons (1995) and are exemplified in certain of the specific compounds used in this invention.
Particularly favored derivatives and prodrugs are those that increase the bioavailability of the compounds of this invention when such compounds are administered to a mammal (e.g., by allowing an orally administered compound to be more readily absorbed into the blood), have more favorable clearance rates or metabolic profiles, or which enhance delivery of the parent compound to a biological compartment (e.g., the brain or lymphatic system) relative to the parent species. Preferred prodrugs include derivatives where a group which enhances aqueous solubility or active transport through the gut membrane is appended to the structure of formula (I).
Pharmaceutically acceptable salts of the compounds of this invention include those derived from pharmaceutically acceptable inorganic and organic acids and bases. Examples of suitable acid salts include acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate, formate, fumarate, glucoheptanoate, glycerophosphate, glycolate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, malonate, methanesulfonate, 2-naphtha-lenesulfonate, nicotinate, nitrate, oxalate, palmoate, pectinate, persulfate, 3-phenylpropionate, phosphate, picrate, pivalate, propionate, salicylate, succinate, sulfate, tartrate, thiocyanate, tosylate and undecanoate. Other acids, such as oxalic, while not in themselves pharmaceutically acceptable, may be employed in the preparation of salts useful as intermediates in obtaining the compounds of the invention and their pharmaceutically acceptable acid addition salts.
Salts derived from appropriate bases include alkali metal (e.g., sodium and potassium), alkaline earth metal (e.g., calcium and magnesium), salts with organic bases, such as dicyclohexylamine salts, N-methyl-D-glucamine, salts with amino acids such as arginine and lysine, ammonium and N-(C1-4 alkyl)4+ salts.
This invention also envisions the quaternization of any basic nitrogen-containing groups of the compounds disclosed herein with such agents as lower alkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides and iodides; dialkyl sulfates, such as dimethyl, diethyl, dibutyl and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides, such as benzyl and phenethyl bromides and others. Water or oil-soluble or dispersible products may be obtained by such quaternization.
In general, compounds of formula (I) are obtained via methods illustrated in the Examples. As can be appreciated by the skilled artisan however the synthetic schemes set forth herein are not intended to comprise a comprehensive list of all means by which the compounds described and claimed in this application may be synthesized. Further methods will be evident to those of ordinary skill in the art. Additionally, the various synthetic steps described above may be performed in an alternate sequence or order to give the desired compounds.
Without being bound by theory, we believe that the compounds of this invention interact either covalently or noncovalently with the active site of the HCV NS3 protease and other serine proteases, inhibiting the ability of such an enzyme to cleave natural or synthetic substrates. Noncovalent interactions are advantageous in that they impart relatively greater specificity of inhibition and will not inhibit other undesirable targets, e.g. cysteine proteases. These compounds will therefore have a greater therapeutic index when administered to mammals than covalent protease inhibitors, which can interact with a wide range of proteases and cause undesirable toxic effects. In contrast, covalent interactions are advantageous in that they impart greater inhibitory potency allowing lower doses may be administered and thus ameliorating any lack of specificity problems.
The novel compounds of the present invention are excellent inhibitors of proteases, particularly serine proteases, and more particularly HCV NS3 protease inhibitors. Accordingly, these compounds are capable of targeting and inhibiting proteases, particularly serine proteases, and more particularly HCV NS3 proteases. As such, these compounds interfere with the life cycle of viruses, including HCV and are thus useful as antiviral agents. Inhibition can be measured by various methods such as the methods of Example 3.
The term xe2x80x9cantiviral agentxe2x80x9d refers to a compound or drug which possesses viral inhibitory activity. Such agents include reverse transcriptase inhibitors (including nucleoside and non-nucleoside analogs) and protease inhibitors. Preferably the protease inhibitor is a HCV protease inhibitor.
The term xe2x80x9ctreatingxe2x80x9d as used herein refers to the alleviation of symptoms of a particular disorder in a patient or the improvement of an ascertainable measurement associated with a particular disorder. As used herein, the term xe2x80x9cpatientxe2x80x9d refers to a mammal, including a human.
Thus, according to another embodiment this invention provides pharmaceutical compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof; an additional agent selected from, but not including, an immunomodulatory agent, such as xcex1-, xcex2-, or xcex3-interferon; other antiviral agents, such as ribavarin or amantadine; other inhibitors of HCV protease; inhibitors of other targets in the HCV life cycle such as helicase, polymerase, or metalloprotease; or combinations thereof and any pharmaceutically acceptable carrier, adjuvant or vehicle. An alternate embodiment provides compositions comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof; and a pharmaceutically acceptable carrier, adjuvant or vehicle. Such composition may optionally comprise an additional agent selected from an immunomodulatory agent, such as xcex1-, xcex2-, or xcex3-interferon; other antiviral agents, such as ribavarin; other inhibitors of HCV protease; inhibitors of the HCV helicase; or combinations thereof.
The term xe2x80x9cpharmaceutically acceptable carrier or adjuvantxe2x80x9d refers to a carrier or adjuvant that may be administered to a patient, together with a compound of this invention, and which does not destroy the pharmacological activity thereof and is nontoxic when administered in doses sufficient to deliver a therapeutic amount of the compound.
Pharmaceutically acceptable carriers, adjuvants and vehicles that may be used in the pharmaceutical compositions of this invention include, but are not limited to, ion exchangers, alumina, aluminum stearate, lecithin, self-emulsifying drug delivery systems (SEDDS) such as dxcex1-tocopherol, polyethyleneglycol 1000 succinate, or TPGS, surfactants used in pharmaceutical dosage forms such as Tweens or other similar polymeric delivery matrices, serum proteins, such as human serum albumin, gelatin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, water, salts or electrolytes, such as protamine sulfate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, polylacetic acid, ployacetic polyglycollic acid, citric acid, cellulose-based substances, such as HPC and HPMC, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polyoxypropylene-block polymers, polyethylene glycol, wool fat. Cyclodextrins such as xcex1-, xcex2-, and xcex3-cyclodextrin, or chemically modified derivatives such as hydroxyalkylcyclodextrins, including 2- and 3-hydroxypropyl-xcex2-cyclodextrins, or other solubilized derivatives may also be advantageously used to enhance delivery of compounds of formula (I).
The pharmaceutical compositions of this invention may be administered orally, parenterally, by inhalation spray, topically, rectally, nasally, buccally, vaginally or via an implanted reservoir. We prefer oral administration or administration by injection. The pharmaceutical compositions of this invention may contain any conventional non-toxic pharmaceutically-acceptable carriers, adjuvants or vehicles. In some cases, the pH of the formulation may be adjusted with pharmaceutically acceptable acids, bases or buffers to enhance the stability of the formulated compound or its delivery form. The term parenteral as used herein includes subcutaneous, intracutaneous, intravenous, intramuscular, intra-articular, intrasynovial, intrasternal, intrathecal, intralesional and intracranial injection or infusion techniques.
The pharmaceutical compositions may be in the form of a sterile injectable preparation, for example, as a sterile injectable aqueous or oleaginous suspension.
This suspension may be formulated according to techniques known in the art using suitable dispersing or wetting agents (such as, for example, Tween 80) and suspending agents. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example, as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are mannitol, water, Ringer""s solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose, any bland fixed oil may be employed including synthetic mono- or diglycerides. Fatty acids, such as oleic acid and its glyceride derivatives are useful in the preparation of injectables, as are natural pharmaceutically-acceptable oils, such as olive oil or castor oil, especially in their polyoxyethylated versions. These oil solutions or suspensions may also contain a long-chain alcohol diluent or dispersant such as those described in Pharmacopeia Helvetica (Ph. Helv.) or a similar alcohol, or carboxymethyl cellulose or similar dispersing agents which are commonly used in the formulation of pharmaceutically acceptable dosage forms such as emulsions and/or suspensions. Other commonly used surfactants such as Tweens or Spans and/or other similar emulsifying agents or bioavailability enhancers which are commonly used in the manufacture of pharmaceutically acceptable solid, liquid, or other dosage forms may also be used for the purposes of formulation.
The pharmaceutical compositions of this invention may be orally administered in any orally acceptable dosage form including, but not limited to, capsules, tablets, and aqueous suspensions and solutions. In the case of tablets for oral use, carriers which are commonly used include lactose, corn starch, dicalcium phosphate and microcrystalline cellulose (Avicel). Lubricating agents, such as magnesium stearate and talc, are also typically added. For oral administration in a capsule form, useful diluents include lactose, dried corn starch and TPGS, as well as the other diluents used in tablets. For oral administration in a soft gelatin capsule form (filled with either a suspension or a solution of a compound of this invention), useful diluents include PEG400, TPGS, propylene glycol, Labrasol, Gelucire, Transcutol, PVP and potassium acetate. When aqueous suspensions are administered orally, the active ingredient is combined with emulsifying and suspending agents, such as sodium CMC, methyl cellulose, pectin and gelatin. If desired, certain sweetening and/or flavoring and/or coloring agents may be added.
The pharmaceutical compositions of this invention may also be administered in the form of suppositories for rectal administration. These compositions can be prepared by mixing a compound of this invention with a suitable non-irritating excipient which is solid at room temperature but liquid at the rectal temperature and therefore will melt in the rectum to release the active components. Such materials include, but are not limited to, cocoa butter, beeswax, gelatin, glycerin and polyethylene glycols.
Topical administration of the pharmaceutical compositions of this invention is especially useful when the desired treatment involves areas or organs readily accessible by topical application. For application topically to the skin, the pharmaceutical composition should be formulated with a suitable ointment containing the active components suspended or dissolved in a carrier. Carriers for topical administration of the compounds of this invention include, but are not limited to, mineral oil, liquid petroleum, white petroleum, propylene glycol, polyoxyethylene polyoxypropylene compound, emulsifying wax, stearic acid, cetyl stearate, cetyl alcohol, lanolin, magnesium hydroxide, kaolin and water. Alternatively, the pharmaceutical composition can be formulated with a suitable lotion or cream containing the active compound suspended or dissolved in a carrier. Suitable carriers include, but are not limited to, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters, wax, cetyl alcohol, 2-octyldodecanol, benzyl alcohol and water. The pharmaceutical compositions of this invention may also be topically applied to the lower intestinal tract by rectal suppository formulation or in a suitable enema formulation. Topically-transdermal patches are also included in this invention.
For ophthalmic use, the pharmaceutical compositions may be formulated as micronized suspensions in isotonic, pH adjusted sterile saline, or, preferably, as solutions in isotonic, pH adjusted sterile saline, either with our without a preservative such as benzylalkonium chloride. Alternatively, for ophthalmic uses, the pharmaceutical compositions may be formulated in an ointment such as petrolatum.
The pharmaceutical compositions of this invention may be administered by nasal aerosol or inhalation. Such compositions are prepared according to techniques well-known in the art of pharmaceutical formulation and may be prepared as solutions in saline, employing benzyl alcohol or other suitable preservatives, absorption promoters to enhance bioavailability, fluorocarbons, and/or other solubilizing or dispersing agents known in the art.
Dosage levels of between about 0.01 and about 100 mg/kg body weight per day, preferably between about 0.5 and about 75 mg/kg body weight per day of the protease inhibitor compounds described herein are useful in a monotherapy for the prevention and treatment of antiviral, particularly anti-HCV mediated disease. Typically, the pharmaceutical compositions of this invention will be administered from about 1 to about 5 times per day or alternatively, as a continuous infusion. Such administration can be used as a chronic or acute therapy. The amount of active ingredient that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. A typical preparation will contain from about 5% to about 95% active compound (w/w). Preferably, such preparations contain from about 20% to about 80% active compound.
When the compositions of this invention comprise a combination of a compound of formula (I) and one or more additional therapeutic or prophylactic agents, both the compound and the additional agent should be present at dosage levels of between about 10 to 100%, and more preferably between about 10 to 80% of the dosage normally administered in a monotherapy regimen.
According to one embodiment, the pharmaceutical compositions of this invention comprise an additional immunomodulatory agent. Examples of additional immunomodulatory agents include, but are not limited to, xcex1-, xcex2-, and xcex4-interferons.
According to an alternate embodiment, the pharmaceutical compositions of this invention may additionally comprise an anti-viral agent. Examples of anti-viral agents include, ribavirin and amantadine.
According to another alternate embodiment, the pharmaceutical compositions of this invention may additionally comprise other inhibitors of HCV protease.
According to yet another alternate embodiment, the pharmaceutical compositions of this invention may additionally comprise an inhibitor of other targets in the HCV life cycle, such as helicase, polymerase, or metalloprotease.
Upon improvement of a patient""s condition, a maintenance dose of a compound, composition or combination of this invention may be administered, if necessary. Subsequently, the dosage or frequency of administration, or both, may be reduced, as a function of the symptoms, to a level at which the improved condition is retained when the symptoms have been alleviated to the desired level, treatment should cease. Patients may, however, require intermittent treatment on a long-term basis upon any recurrence of disease symptoms.
As the skilled artisan will appreciate, lower or higher doses than those recited above may be required. Specific dosage and treatment regimens for any particular patient will depend upon a variety of factors, including the activity of the specific compound employed, the age, body weight, general health status, sex, diet, time of administration, rate of excretion, drug combination, the severity and course of the infection, the patient""s disposition to the infection and the judgment of the treating physician.
When these compounds or their pharmaceutically acceptable salts are formulated together with a pharmaceutically acceptable carrier, the resulting composition may be administered in vivo to mammals, such as man, to inhibit serine proteases, particularly HCV NS3 protease or to treat or prevent viral infection, particularly HCV virus infection. Such treatment may also be achieved using the compounds of this invention in combination with agents which include, but are not limited to: immunomodulatory agents, such as xcex1-, xcex2-, or xcex3-interferons; other antiviral agents such as ribavirin, amantadine; other inhibitors of HCV NS3 protease; inhibitors of other targets in the HCV life cycle such as helicase, polymerase, metalloprotease, or internal ribosome entry; or combinations thereof. These additional agents may be combined with the compounds of this invention to create a single dosage form. Alternatively these additional agents may be separately administered to a mammal as part of a multiple dosage form.
Accordingly, another embodiment of this invention provides methods of inhibiting serine protease activity in mammals by administering a compound of the formula (I), wherein the substituents are as defined above. Preferably, the serine protease is HCV NS3.
In an alternate embodiment, the invention provides methods of inhibiting HCV or HCV NS3 activity in a mammal comprising the step of administering to said mammal, a compound of formula (I), wherein the substituents are as defined above.
In an alternate embodiment, this invention provides methods of decreasing serine protease activity in a mammal comprising the step of administrating to said mammal any of the pharmaceutical compositions and combinations described above. If the pharmaceutical composition comprises only a compound of this invention as the active component, such methods may additionally comprise the step of administering to said mammal an agent selected from an immunomodulatory agent, an antiviral agent, a HCV protease inhibitor, or an inhibitor of other targets in the HCV life cycle. Such additional agent may be administered to the mammal prior to, concurrently with, or following the administration of the HCV inhibitor composition.
In a preferred embodiment, these methods are useful in decreasing HCV NS3 protease activity in a mammal. If the pharmaceutical composition comprises only a compound of this invention as the active component, such methods may additionally comprise the step of administering to said mammal an agent selected from an immunomodulatory agent, an antiviral agent, a HCV protease inhibitor, or an inhibitor of other targets in the HCV life cycle such as helicase, polymerase, or metalloprotease. Such additional agent may be administered to the mammal prior to, concurrently with, or following the administration of the compositions of this invention.
In an alternate preferred embodiment, these methods are useful for inhibiting viral replication in a mammal. Such methods are useful in treating or preventing, for example, viral diseases, such as HCV. If the pharmaceutical composition comprises only a compound of this invention as the active component, such methods may additionally comprise the step of administering to said mammal an agent selected from an immunomodulatory agent, an antiviral agent, a HCV protease inhibitor, or an inhibitor of other targets in the HCV life cycle. Such additional agent may be administered to the mammal prior to, concurrently with, or following the administration of the composition according to this invention.
The compounds set forth herein may also be used as laboratory reagents. The compounds of this invention may also be used to treat or prevent viral contamination of materials and therefore reduce the risk of viral infection of laboratory or medical personnel or patients who come in contact with such materials. These materials include, but are not limited to, biological materials, such as blood, tissue, etc; surgical instruments and garments; laboratory instruments and garments; and blood collection apparatuses and materials.
In order that this invention be more fully understood, the following examples are set forth. These examples are for the purpose of illustration only and are not to be construed as limiting the scope of the invention in any way.
Compounds 101 through 109 were prepared using the generic synthesis scheme 1, depicted below. Synthesis of specific compounds are described in the following examples.
The correct (M+H)+ and/or (M+Na)+ molecular ions for all compounds as set forth in Table 2 were obtained by either matrix-assisted laser desorption mass spectrometry (Kratos MALDI I) or by electro spray mass spectrometry (MICROMASS Quatro II).
Numerous amino acids for use in the synthesis of peptidyl and peptidomimetic compounds of this invention may be purchased commercially from, for instance, Sigma Chemical Company or Bachem Feinchemikalien AG (Switzerland). Amino acids that are not commercially available can be made by known synthetic routes (xe2x80x9cKinetic Resolution of Unnatural and Rarely Occurring Amino Acids: Enantioselective Hydrolysis of N-Acyl Amino Acids Catalyzed by Acylase Ixe2x80x9d, Chenault, H. K. et. al., J. Am. Chem. Soc. 111, 6354-6364 (1989) and references cited therein; xe2x80x9cSynthesis of xcex2-xcex3-Unsaturated Amino Acids by the Strecker Reaction, Greenlee, W. J., J. Org. Chem. 49, 2632-2634 (1984); xe2x80x9cRecent Stereoselective Synthetic Approaches to Beta-amino Acidsxe2x80x9d, Cole, D. Tetrahedron 50: 9517 (1994); xe2x80x9cThe Chemistry of Cyclic Alpha Imino Acidsxe2x80x9d, Mauger, A.B; Volume 4 of xe2x80x9cChemistry and Biochemistry of Amino Acids, Peptides, and Proteinsxe2x80x9d, Weinstein, B. editor, Marcel Dekker (1977); xe2x80x9cRecent Progress in the Synthesis and Reactions of Substituted Piperidinesxe2x80x9d, Org. Prep. Procedure int. 24, 585-621 (1992), all of which are incorporated herein by reference).
Certain compounds of formula (I) may be synthesized from amino acids by procedures which are well known in the art of peptide and organic chemical synthesis. Examples of such syntheses are generally set forth in Bodanszky and Bodanszky, xe2x80x9cThe Practice of Peptide Synthesisxe2x80x9d, Springer-Verlag, Berlin, Germany (1984), xe2x80x9cThe Peptidesxe2x80x9d, Gross and Meinhofer, eds.; Academic Press, 1979, Vols. I-III, and Stewart, J. M. and Young, J. D., xe2x80x9cSolid Phase Peptide Synthesis, Second Editionxe2x80x9d, Pierce Chemical Company, Rockford, Ill. (1984); and xe2x80x9cRecent Advances in the Generation of Molecular Diversityxe2x80x9d, Moos, W. H., Green, G. D. and Pavia, M. R. in xe2x80x9cAnnual Reports in Medicinal Chemistry, Vol. 28xe2x80x9d pp. 315-324; Bristol, J. A., ed.; Academic Press, San Diego, Calif. (1993), all of which are incorporated herein by reference.
Typically, for solution phase synthesis of peptides, the xcex1-amine of the amino acid to be coupled is protected by a urethane such as Boc, Cbz, Fmoc or Alloc while the free carboxyl is activated by reaction with a carbodiimide such as DCC, EDC, or DIC, optionally in the presence of a catalyst such as HOBT, HOAt, HOSu, or DMAP. Other methods, which proceed through the intermediacy of activated esters, acid halides, enzyme-activated amino acids and anhydrides including phosphonium reagents such as BOP, Py-BOP, N-carboxy-anhydrides, symmetrical anhydrides, mixed carbonic anhydrides, carbonic-phosphinic and carbonic-phosphoric anhydrides, are also suitable. After the peptide has been formed, protecting groups may be removed by methods described in the references listed above, such as by hydrogenation in the presence of a palladium, platinum or rhodium catalyst, treatment with sodium in liquid ammonia, hydrochloric, hydrofluoric, hydrobromic, formic, trifluoromethanesulfonic, or trifluoroacetic acid, secondary amines, fluoride ion, trimethylsilyl halides including bromide and iodide, or alkali. Automation of the synthetic process, using techniques such as those set forth above, can be accomplished by use of commercially available instrumentation, including but not limited to the Advanced Chemtech 357 FBS and 496 MOS; Tecan CombiTec, and Applied Biosystems 433A among others. Specific application of these methods and their equivalents, depending upon the target compound, will be apparent to those skilled in the art. Modifications of chemical processes and choice of instrumentation is within the skill of the ordinary practitioner.
Although some of the schemes depicted below indicate particular stereochemistry for certain groups, it should be apparent to those of skill in the art that the synthesis schemes may be modified to allow for the use of those certain groups having the opposite stereochemistry. Therefore, the indication of stereochemistry in these scheme is not intended to limit the depicted synthesis to any particular stereochemistry of any intermediate or final product. 